I have read about inflation but I really don't understand why it's needed? Could someone explain? The idea is that inflation tells you why the universe is so uniform right? So lets assume the Big Bang starts with a singularity. From this emerges an infinite number of particles - bosons - which either become part of the background radiation or decay into matter-antimatter pairs. If the position of each particle after a Plank time say is entirely random, the probabilities of the positions of the particles in any finite area should follow a Poission distribution. OK, so the Universe the instant after the Big Bang is homogeneous and isotropic. So where does the clumpiness or variations curvature and temperature come from that inflation is needed to remove? Does the clumpiness form shortly after the Big Bang and then have to be removed again by inflation? They say how can the Universe be homogeneous if it has not had the chance to interact with other regions? But surely if everything started at a singularity then everything WAS in the same place and time at one point. Does cosmic background radiation not follow a Poisson distribution? Are they saying that if the Universe just expanding linearly, say, that it (the background radition) would clump together through gravity? Or that gravitational waves would make the Universe less flat?